Numerous variations of bicycles, tricycles, and other vehicles are known in the prior art, for providing excellent devices for exercise and transportation. However, these vehicles typically have used only the operator's legs moving in a circular motion as a means to provide power. This exclusive reliance on leg power significant inhibits the potential exercise benefits, which could be enhanced if the device were to utilize both the arms and the legs to provide power. Similarly, utilizing the power of the arms to supplement that provided by the legs could allow greater speeds to be achieved and maintained. In addition, persons without the use of their legs, and who would not be able to use a conventional leg-powered cycle, could nonetheless operate a vehicle, which utilized arm power.
Several cycle designs utilising both arm and leg power are known in the prior art. One example is shown in U.S. Pat. No. 1,020,432 to McBarnes, which discloses a bicycle powered by a linear reciprocating motion of the arms and legs. However, the McBarnes cycle requires simultaneous use of the arms and legs, which deprives the operator of the option of choosing an optimum combination of arm and leg usage. In addition, such a device would not be suitable for people that are handicapped in the use of their legs.
Another example is shown in U.S. Pat. No. 4,928,986 to Carpenter, which discloses a bicycle powered by the operator's arms and legs. Carpenter utilises a chain driven gear on a pulling or drive stroke. This limits the exercise to one-half of the operator's total motion.
Various attempts have been made to solve this problem, but the solutions have often required cumbersome and heavy equipment. In addition, the prior art configurations have also sometimes rendered operation of the vehicle awkward, and in particular have had less than optimum results with steering the vehicles. Examples of vehicles that permit the arms and legs to be used jointly or independently are shown in U.S. Pat. Nos. 3,760,905 to Dower and 4,508,358 to Erel. Further examples of background art may be seen in U.S. Pat. No. 4,541,647 to Braun and Soviet Union Patent No. 1,065,279.
What is desired is a manually operated drive system, which can be operated by an operator's arms, legs, or both. It is desirable that the apparatus provide resistance to the operator during all directions of the stroke.